Maybe it's not really needed, at least this is what configure.ac says about it:

dnl check for missing libraries and disable them.
if test x"$BOOST_LIBS" != x; then
if test x"${cygnal_missing_libs}" != x; then
for i in ${cygnal_missing_libs}; do
if test $i = serialization; then
AC_DEFINE([BOOST_MULTI_INDEX_DISABLE_SERIALIZATION], ["1"], [if the library is missing, don't use it.])
fi
done
fi
fi

Anyway, the problem is that ERROR is printed to filedescriptor 4 rather than 3... as if it was a warning. If it's just a warning it should be reworded.